Brain Function: Novel Technologies Driving Novel Understanding - Bioinspired Approaches for Human-Centric Technologies - page 299

a b c

d

Fig. 10.1 Manipulating the electrical activity of layer V cortical neurons. (a) Opsins were
selectively expressed in layer V neurons combining the use of the Rbp4-Cre mouse line with
viral injections of adeno-associated viruses. (b-d) Cells expressing the transgenes (ChR2) were
regular firing cells (b), display sub-millisecond membrane depolarizations when illuminated with
blue light (c), and have the typical morphology of pyramidal neurons (d). Modified from Beltramo
et al. Nature Neuroscience (2013)

superior colliculus, and trigeminal nuclei. It has long been recognized that this
anatomical and functional specialization among cortical cells in different layers
could serve different functional roles in cortical circuit dynamics. However, a direct
and causal demonstration of this hypothesis has long been prevented due to the lack
of tools to manipulate the activity of specific cellular subpopulations in vivo. IIT
neuroscientists have used optogenetics, which allows the remote control of cellular
excitability with light, to investigate the role of excitatory neurons located in layers
II/III and V in the propagation of cortical network dynamics, using slow oscillations
as an experimental model (Beltramo et al. 2013 ; Fig. 10.1 ).
By combining selective expression of excitatory and inhibitory opsins in layer V
and layer II/III pyramidal neurons with electrophysiological recordings in anesthe-
tized mice in vivo, we showed that activation/inactivation of a subset of pyramidal